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Stormwater Facility Information

ODOT's Hydraulics Program monitors stormwater facilities, the operations and maintenance manuals located at each facility, as well as related program data. ODOT maintains more than 1,000 facilities statewide.

Please refer to the Hydraulics Manual for additional information and project requirements, or contact the Hydraulics Program staff.

​Site Identification

Each stormwater facility is assigned a unique drainage facility identification number. The DFI number is used to link the facility with an operations and maintenance manual and with ODOT's asset management systems.

Obtaining a Drainage Facility ID

Contact the Hydraulics Program lead during PS&E to obtain a DFI number.

Please refer to chapter 17 of the Hydraulics Manual for additional information.

Accessing Stormwater Inventory Information

ODOT's stormwater inventory is available through TransGIS​, a web-based program, accessible to anyone.

Viewing Operations and Maintenance Manuals

  1. ​​Once in TransGIS, select "Drainage" from the menu on the left.
  2. Select "Stormwater Management Facilities."
  3. Select "Apply" at the bottom of the screen.
  4. Facilities will be noted by a green marker on the map. You may view the manual of any facility with a corresponding blue "I" button.
  5. Once a site is selected, facility information and links to the manual and maintenance tables will open.

Each stormwater facility is required to have a dedicated operations and maintenance manual that describes:

  • The type of facility.
  • How the facility operates.
  • Outlines the inspection schedule.
  • Summarizes required maintenance work.

Guidance on the preparation of an operations and maintenance manual can be found in chapter 4 of the Hydraulics Manual.

Stormwater facility maintenance work is summarized in the following series of tables. Maintenance actions depend on the facility type.

Table 1 - General Maintenance

Table 2 - Maintenance of Stormwater Ponds

Table 3 - Maintenance of Water Quality or Biofiltration Swales

Table 4 - Filter Strips

Table 5 - Bioslopes

Table 6 - Detention Vaults

Table 7 - Detention Tank (or Large Diameter Pipe)

Table 8 - Underground Injection Controls (UICs)​

*S = Special maintenance requirements. Please refer to the respective Operations and Maintenance Manual for information about the special requirements.


ODOT is required to hold a National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Permit​​ issued by the Oregon Department of Environmental Quality to operate the ODOT stormwater system. The permit requires ODOT to inventory and manage stormwater outfalls associated with the ODOT stormwater system. ODOT has prepared an inventory of its stormwater outfalls, but these records can be difficult to read and understand.

Stormwater outfalls are one of several stormwater treatment facility components specially configured to assist with the conveyance of runoff before leaving the state’s highway system and entering a receiving water body. Outfalls typically convey water from either a stormwater treatment facility or a stormwater piping system to a point of discharge, where water enters a natural water body or another drainage conveyance system.

Stormwater outfalls are integral parts of the state highway system and like other infrastructural elements, they are subject to deterioration. ODOT is responsible for maintaining these components as part of its operation and maintenance of stormwater treatment facilities, in an effort to more effectively remove highway pollutants from stormwater runoff before they re-enter the natural environment.

In support of the NPDES MS4, ODOT has provided an inventory of its stormwater outfalls located along the state’s highways. The focus is on outfall pipes discharging to a water body.

Outfall Inventory Project

ODOT has begun a new project where new and existing ODOT outfall information is being collected and formatted so a GIS map can be produced that clearly depicts location of ODOT outfalls. The project is focused specifically on mapping ODOT outfalls located in MS4 NPDES permit areas because DEQ has identified these areas as high risk for stormwater impacts to receiving waters.

Long Term Effort

ODOT has been working for a number of years on organizing highway inventory information into a format that is more usable for GIS mapping. This project is part of that effort. ODOT’s long term goal is to eventually produce maps that depict various highway features associated with ODOT right of way, stormwater outfalls being one of those highway features. A summary of ODOT outfall inventory information gathered to date for this project. ODOT is currently in the process of developing a user-friendly map that will be posted soon.

Data Collection

Over 600 stormwater outfalls have been inventoried within Phase I/II municipal boundaries and are shown in the map files listed below:

  • Bend
  • Corvallis/Philomath
  • Eugene/Springfield
  • Medford/Ashland
  • Portland
  • Salem/Keizer

Ditch Inspection

An important task of ODOT Maintenance is keeping the highway drainage system functioning. Roadside ditches are cleaned and reshaped, removing accumulated sediment and debris that reduces capacity and restricts flow. As part of it's Ditch Inspection Program, ODOT also inspects and cleans highway ditches to ensure adequate structural status and to protect water quality. The Ditch Maintenance Log (June 2010 to present) is a quarterly report that shows which state highway ditches have been maintained and the cost of that maintenance.​